Thanks folks! I have surrendered my earlier fantasy of proceeding numerically by designation. I'm afraid that it's an organizational dog's breakfast from here on

Un Colpo di Fulmine! - The Aer.Macchi C.201ter Fighter-Bomber

The Macchi C.201 was intended as a higher-powered derivative of the C.200 Saetta ... but that didn't pan out. With the cancellation of Fiat's 1,000 hp A.76 R.C.40 engine, that original C.201 approach foundered. So, for the near-complete prototype C.201 (MM.436), the airframe was simply adapted for the C.200's A.74 R.C.38. The C.201's finer fuselage design resulted in some performance gain ... but not enough.

Pure horsepower was required to gain the performance that Mario Castoldi's knew his fighter's airframe was capable of. At Castoldi's instigation, a Daimler Benz DB 601A-1 engine was imported from Germany. The Ministero dell'Aeronautica then acquire license-production rights on behalf of Alfa Romeo who would build this engine for Italian use as the R.A.1000 R.C.41-I. Accordingly, the MdA ordered another C.201 airframe (MM.445) to be completed with an imported Daimler Benz engine. This aircraft flew as the prototype C.202 Folgore in August 1940.

It would take Breda another 8 months to rejig C.200 tooling at Sesto San Giovanni for C.202 production and over a year before the first operational Folgore fighter would see service with the Regia Aeronautica. In the meantime, at their Varese factory, Aer.Macchi had begun turning out similar C.204 fighters powered by domestic Isotta-Fraschini Asso L.121 R.C.40 upright V-12s. However, I-F's L.121 output was quite limited and Alfa Romeo's deliveries rarely exceeded fifty R.A.1000s per month. [1] With such a paltry output of new fighters, the MdA concluded that the mediocre C.200 would also need to be retained in production.

Aeronautica Macchi put forward an alternative proposal. Rather than continuing Saetta production, Aer.Macchi proposed a revised C.201 concept. This new aircraft - identical to the C.202 and C.204 aft of the firewall - would be powered by the Saetta's lower-powered Fiat A.74 radial engine. Superior performance (compared with the C.200, at least) would be assured by the higher fineness ratio inherent in employing the slimmer C.202/C.204 fuselage. The Saetta's fuselage 'hump' had now disappeared altogether, made possible by slipping the new fighter's gun barrel's in between the Fiat radial's cylinder heads.

The Ministero dell'Aeronautica accepted Aer.Macchi's proposal, now designated C.201ter. [2] The first machine would be created from the unfinished second prototype C.201 (MM.437). [3] Using many C.204 components, the prototype C.201ter came together very quickly. Compared with the original C.201 (or, indeed the C.200), the C.201ter had revised engine mounts with an accordingly higher thrust line. As noted, the barrels of the twin 12.7 mm Breda-SAFAT guns passed between the cylinders on the C.201ter. The higher engine mounts also resulted in a completely revised exhaust manifold system.

Top The prototype C.201ter (MM.437) as rolled out at Lonate Pozzolo (Varese) airfield.

Production of the C.201ter commenced very smoothly and the aircraft were interspered among the C.204s at Varese-Schiranna (C.201terserie I) and C.202s at Breda, Sesto S. Giovanni/Bresso (serie II). [4] Initial production C.201ters differed little from the prototype. Breda introduced the C.201terserie IV with additional 7.7 mm wing guns but this was overshadowed by Aer.Macchi's serie III - the C.201ter-cb (caccia bombardiere), a fighter-bomber adaptation with twin wing racks. Most were intended for use in Libya (Africa Settentrionale) and later serie III aircraft were fitted with built-in dust filters similar to those of C.202s.

Top An early production C.201ter-ch/AS fighter-bomber. This aircraft has been 'Africanized' but lacks the later-style carburettor intake with integral dust filter._________________________________

[1] It had been hoped that Alfa production would augment DB 601A imports but Germany was reluctant to release many Daimler Benz engines for export.

[2] The C.201bis was an unbuilt version of the A.76-powered C.201 with added 7.7 mm wing guns. The C.201ter was dubbed Fulmine (Lightning Bolt) but this name found no popular usage (perhaps, being confusingly similar in meaning to Folgore).

[3] MM.437 was originally scheduled to become the first prototype C.204. However, in the end, a pre-production C.202 airframe was re-engined as the first C.204.

[4] When Aer.Macchi transferred C.204 production to the SocietÓ Aeronautica Italiana 'Ambrosini' plant across town, SAI Ambrosini also took over Macchi's C.201ter production.

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Feeling confident in its Caccia (Intercettori) choices, the Ministero dell'Aeronautica issued an open Richiesta di Pareri (Request for Proposals) for high-altitude interceptors based upon in-service monoplane fighter airframes. Performance demands were extreme - including an operating altitude of at least 15,000 metres [1] - but submitting design offices could expect technical assistance from the Regia Aeronautica's Direzione superiore del Genio e delle Costruzioni Aeronautiche (DGCA). Still, this 'Caccia Alta Quota' requirement was daughting for the then-current state of aviation technology in Italy.

Useful performance data was being gleaned by the Reparto Alta Quota, 1░ Centro sperimentale (High Altitude Department, 1st Experimental Centre) based at Montecelio-Guidonia outside Rome. There, a specially modified Caproni Ca.161 biplane was being put through its high-altitiude paces. Initial trials had been performed with the pilot wearing a full pressure suit. Later, as modified Ca.161bis, this airframe was fitted with full pressure cabin. Both pressurization approaches were incorporated as alternatives in Dott. Ing. Castoldi's response to the Ministero dell'Aeronautica 'Caccia Alta Quota' requirement.

Macchi submitted two Saetta-based proposals for the 'Caccia Alta Quota' requirement. The first - and Castoldi's preferred approach - was the C.200 TP (for Tuta Pressurizzata or pressure suit). The second submission was the C.200 CS (for Cabina Stagna or pressure cabin). To Ing. Castoldi's chagrin, the MdA chose to pursue the back-up C.200 CS approach with full pressure cabin. [2]

A High-Altitude Saetta - The Macchi C.200AQ

The C.200 CS concept was refined into the airframe built as the prototype C.200AQ (for Alta Quota or High Altitiude). By comparison with a standard Saetta, the C.200AQ had greatly extended wingtips complete with longer-span ailerons. Power was provided by a specially-built Fiat A.74 R.C.150 engine aspirated by a Fiat-developed turbosupercharger (based upon Fiat's license for the US General Electric Type-B turbo). This turbo was mounted semi-externally on the portside of the forward fuselage, matched on the starboard side by an intercooler. The now-detachable, semi-monocoque rear fuselage sandwiched a new pressure cabin between it and the forward fuselage/wings section.

The C.200AQ pressure cabin was based directly on the Cabina Stagna of the Ca.163bis experimental aircraft. This pressure cabin was supplied to Aer.Macchi by the Regia Aeronautica's Reparto Alta Quota (High Altitude Department) at Montecelio-Guidonia. Although the C.200AQ lost much of its commonality with the standard Saetta, the readily-dismantled airframe was seen as an advantage for testing in a pressure chamber. Alas, that very ability led directly to the C.200AQ's downfall. In August 1940, the C.200AQ engine and forward fuselage were placed in the pressure chamber at Montecelio-Guidonia. At a simulated altitude of 12,000 m, the Fiat turbosupercharger exploded and the airframe caught fire inside the chamber. The forward airframe was badly damaged in the resulting blaze. [3] This was the end for the unflown Macchi C.200AQ airframe.

A Second Arrow in the Quiver - Or, Macchi's High-Altitude Alternative

It is not quite fair to say 'the end' for the C.200AQ airframe. That aircraft's high-altitude wings and detachable rear fuselage were not in the Montecelio-Guidonia pressure chamber on that fateful day in August 1940. Although it now seemed inevitable that Fiat would be awarded the 'Caccia Alta Quota' contract, Ing. Castoldi was not yet ready to throw in the towel. Instead, Castoldi had another plan for the remains of the C.200AQ. Isotta-Fraschini had approach the [/i]Dottore-ingeniore[/i] with an alternative for a high-altitude interceptor. This scheme involved the use of the Asso L.121 V-12 engine mated with twin Szydlowski-Planiol type turbosuperchargers which had been developed in-house at Isotta-Fraschini.

As this new approach would be a private-venture from Macchi and Isotta-Fraschini, Castoldi had a freer hand in its design. Initially, the plan was to revive the Tuta Pressurizzata (pressure suit) approach. However, trials revealed that the turbos were likely to give a diminishing return above 12,500 m. If the planned service ceiling was lowered from 15,000+ m to 13,500 m, a lighter and less structurally-demanding pressure cabin could be constructed. And this was the approach adopted for what became the Macchi C.204AQ.

A triple-walled aluminium Cabina Stagna was constructed for this high-altitude interceptor design. In the C.200AQ, steel-tube trusses had connected the fore and aft fuselage sections while also cradling the larva-like pressure cabin. In contrast, in the C.204AQ, the lighter-weight Cabina Stagna itself formed a central fuselage structure (to which the wings and fore-and-aft sections when then attached). So, despite its designation, the C.204AQ had little affinity with the C.204 fighter other than their base engine types. The C.204AQ was, in effect, a C.200AQ powered by a turbosupercharged Asso L.121 engine. With twin turbos taking up much of the forward fuselage space, the intercooler was relocated to a large belly 'bath' (shared with the engine coolant radiator).

One other connection between the two Macchi high-altitude types was their propellers. The C.200AQ sported a variable-pitch propeller of original design by F.I.E.T. (Fabbrica Italiana Eliche Torino). [4] The propeller had a novel, airstream-driven variable-pitch mechanism (fed by a venturi intake in the nose of its spinner). While the pitch mechanism proved somewhat unreliable, the propeller's broad-chord paddle blades were thought ideal for high altitude performance. The C.204AQ featured a hybrid propeller system. The hub and pitch mechanism were derived from the proven Piaggio P.1004 propeller of the standard C.204 fighter. To this hub were mated new F.I.E.T. wooden paddle blades. Overall, compared with the C.200AQ, the C.204AQ's simpler structure and less high-strung powerplant, seemed to assure success for the new interceptor.

Bottom Prototype C.204AQ as first test flown by Ten.Col. Mario Pezzi of the 1░ Centro sperimentale (1st Experimental Centre), Reparto Alta Quota at Montecelio-Guidonia, December 1940. The heavy cockpit cover with distinctive 'porthole' openings was applied only to the prototype which was intended to test the limits of the Macchi airframe's high altitude performance. Production C.204AQ aircraft were fitted with a clear-view, multi-framed perspex canopy.

______________________________

[1] This RdP represented an optimistic requirement. In October 1938, the highly-experimental Caproni Ca.161bis - a pressure cabin-equipped biplane - had only just achieved an altitude of 15,000 m.

[2] This Macchi development contract was matched with a similar contract for Fiat to build a G.50bis/AQ prototype and further study contracts for Meridionali (for IMAM Ro.51-based interceptors) and Breda (for a high-altitude derivative of the unbuilt Ba.100). By this stage, OM Reggiane SpA had withdrawn its Re.2000-based submission.

[3] In the aftermath of the 17 August 1940 blaze, it was concluded that only the Cabina Stagna was worth saving. After its recovery, the pressure cabin was returned to the DGCA. The other charred remains of the C.200AQ forward fuselage were later scrapped.

[4] F.I.E.T. was better know for its 2-bladed, fixed-pitch propellers for Italian-made light aircraft. While inexperienced at high-performance, constant-speed props, F.I.E.T. had plenty of experience with designing and creating wooden propeller blades.

« Last Edit: Yesterday at 04:51:59 AM by apophenia »

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Thanks guys! The turbos may be a little over-scorched for prototypes ... but it's more fun to render them that way

Before moving on to the Macchi C.205, a bit of background history and designation de-tangling ...

As is fairly common with wartime aircraft evolutions, the begats and designation sequences get confused by 'interim' designs filling an immediate requirement. Such is the case with C.205 variants. Best known is the C.205V Veltro which, as noted earlier, began as the C.202bis. The C.202bis was a 'least mod' approach to applying the more powerful Daimler Benz DB 605A-1 engine - and its Italian-built equivalents - to the C.202 airframe.

The Fiat R.A.1050 R.C.58-I Tifone engine was the Italian-licensed DB 605A-1 meant to replace the less-powerful and lower altitude-rated Alfa Romeo-built DB 601A-1 - the R.A.1000 R.C.41-I. Aft of the firewall, the C.202bis was to be essentially identical to the late production C.202 serie X airframe. Such a development had the obvious advantage of minimal disruption to production of the Macchi fighter - by then, being built by Aeronautica Macchi at Varese-Schiranna (55 km north of Milan), by nearby SocietÓ Aeronautica SAI Ambrosini also of Varese, and by Breda (Societa Italiana Ernesto Breda) at Sesto San Giovanni (8 km northwest of Milan).

The prototype C.202bis - a converted C.202 serie X airframe - flew on 19 April 1942. Powered by an imported DB 605A-1, the C.202bis differed externally from the standard R.A.1000-powered C.202 in having a slightly larger spinner, twin annular oil coolers beneath the cowling, and a semi-retractable tail wheel. Soon after this first flight, the Ministerio dell'Aeronautica applied a new designation scheme for all Tifone-powered fighters. Henceforth the C.202bis was to be referred to as the C.205 - the last number in that designation indicating a new Tifone-powered fighter. [1]

Specifically, the C.202bis became the C.205V Veltro. Most sources translate 'Veltro' as a generic 'greyhound'. And it can be ... although levriero is a more common Italian term for a greyhound. More properly, Veltro is the symbolic saviour of Italy in Danteĺs Inferno (and, obviously, it was hoped in mid-1942 that Macchi's C.205V Veltro would now become a saviour of Benito Mussolini's faltering Fascist regime). So, Veltro is an apt name for a heroic defender but, as we'll see, a name that also excludes the C.205V from the company of the other Tifone-powered fighters.

(To be continued ...)________________________

[1] That 'last 5' would be applied to the Macchi C.205V and C.205N Orione, Fiat G.55 Centauro, Reggiane Re.2005 Sagittario, and Caproni-Vizzola F.6M (the F.6Z being I-F Zeta-powered). For whatever reason, Caproni (Taliedo) and Caproni Bergamasca projects with Tifone engines never seemed to receive '6' designations

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There were several wartime foreign operators of inline-engined Macchi fighters. Luftwaffe units briefly flew Macchi C.202s as did the Air Force of the Independent State of Croatia, the Zrakoplovstvo Nezavisne Dr×ave Hrvatske (ZNDH). Both foreign air forces would also later operate the more powerful C.205V Veltro. For several months near the end of 1943, Germany's JG 77 (of II. Gruppe) flew requisioned Macchi C.205V fighters. [1] The ZNDH would also receive Veltros in the summer of 1944. But, by then, Allied bombing had seriously hampered Aeronautica Macchi's ability to deliver newly-produced fighters. [2]

Top Macchi C.205V (aka Ma 205G-1) flown by ZNDH Bojnik (Major) Josip Helebrant from Zagreb late in the war.

Ironically, there had been discussions at the highest level within the Luftwaffe about adopting the Italian C.205V for German service. [3] Macchi designated aircraft for Luftwaffe orders as C.205G (for Germania). However, the war was turning against the Axis. After initial deliveries to the Luftwaffe of C.205G-2s, [4] it was decided - in the Autumn of 1944 - to relocate Macchi production to the Reich. Accordingly, trainloads of tooling and completed Macchi components (for both the C.205V and C.202) began to be shipped north. Plans were to assemble Macchi components at Wiener Neustadt in Austria. [5] Initially, disruption of Bf 109 production at WN had been judged acceptable but, later on, cooler head prevailed. Instead, the trains rolled on north heading for Trautenau in the Sudetenland.

At Trautenau, Macchi assembly was begun in a former textile mill near a large AEG plant. [6] Here, out of easy Allied bombing range from Italian bases, assembly proceeded fairly smoothly. The first Trautenau-assembled model was essentially similar to the C.205T-2 other than MG131 heavy machine guns replacing the cowl-mounted 12.7mm Breda-SAFAT guns. These aircraft were designated Macchi Ma 205T-3 using the new RLM maker's prefix. [7] The wing-mounted MG 151/20 cannons remained the same. The Ma 205T-4 was a rather less capable fighter - having lost the pair of cannons - and all were completed as photo-reconnaissance fighters. [8]

The first fully-'Germanized' Trautenau Macchi was the Ma 205T-5. This model abandoned the cowl guns in favour of a motor-kanone while retaining the 2 cm wing guns. The adoption of a VDM propeller in a Messerschmitt-type spinner quickly distinguished the Ma 205T-5 from earlier Macchis. Later-production Ma 205T-5s also introduced a clear-blown 'Beule' canopy, replacing the original, heavily-framed Macchi cockpit cover. Two variants of the Ma 205T-5 were produced side-by-side on the Trautenau production line. The Ma 205T-5/B was armed with a long-barrelled 3 cm MG103 cannon. The better-balanced Ma 205T-5/C was armed with the short-barrelled 3 cm MG108 auto-cannon. [9]

Bottom German-assembled Macchi Ma 205T-5 of an unknown unit at Trautenau, B÷hmen, in late April 1945.

A prototype Ma 205T-6 fitted with an DB 605ASM engine was finished in February 1945 but shortly afterwards, the Flugzeugwerke Trautenau factory was heavily damaged by USAAF bombing. Contemporary Allied intelligence bulletins make mention of a 'Ma 205T-7' but the existence of this sub-type could never be confirmed after the Red Army occupied the Trautenau facility.

___________________________

[1] JG 77 flew Veltros from October to December 1943 when the unit re-equipped with new Messerschmitt Bf 109Gs.

[2] After an aborted attack on 25 April 1944, a large USAAF formation pounded Macchi's Varese factory on 01 May 1944. This B-17 raid left both the Macchi plant at Varese and its Breda licensee at Sesto San Giovanni/Bresso in flames. What was left of Italian C.205V production was now destroyed.

[3] It was agreed between Reichsmarschall Hermann G÷ring, General der Jagdflieger Adolf Galland, and others, that the Macchi fighter had an excellent performance for its power. But the primarly incentive to take on the Italian fighter was to challenge what many in the LUftwaffe saw as growing complacency among German aircraft designers and manufacturers.

[4] Within this new designation system, requisioned Macchi C.205V with 'Germanized' instrumentation became C.205T-1s. The C.205T-2 model was similar but fitted with German radios and other Luftwaffe-standard equipment.

[5] In part, Wiener Neustadt was chosen for the ease with which completed fighters could be delivered to the RSI for use by the Aeronautica Nazionale Repubblicana.

[6] As it happens, this facility had an aviation connection - having been the EFW factory during WWI. Connections to the AEG plant had less savoury connections - such proximity allowing Flugzeugwerke Trautenau GmbH access to the local forced labour camps.

[7] The Reichsluftfahrtministerium assigned the prefix 'Ma' for Macchi designs and the type designation 8-205 for the C.205V. For record-keeping purposes, German-controlled C.205V-1 and 'V-2 fighters were given the retroactive designations Ma 205G-1 and Ma 205G-2. For unknown reasons, the RLM retained the Ministero dell'Aeronautica's 'G' for Germania designation suffix.

[8] The Macchi Ma 205T-4 recce-fighters were 'cannon-less' because they were hybrid airframes which combined C.205V fuselages with C.202 wings. Adapting these airframes for photo-reconnaissance was quicker than modifying the wings for [serie] III C.205V-style Mauser cannons. The Ma 205T-4s were fitted with RB 32/7 cameras.

[9] The planned Ma 205T-5/A with a 2 cm Mauser MG151/20 motor-kanone was never produced.

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